Temperature-Stress Bimodal Sensing Conductive Hydrogel-Liquid Metal by Facile Synthesis for Smart Wearable Sensor.

Conductive hydrogels have attracted great attention due to their promising applications in wearable sensors. However, developing conductive hydrogels with excellent sensor properties and multiple stimulus responsive for smart wearable devices is still a challenge. This paper presents a facile synthetic method of a crosslinked chitosan quaternary ammonium salt and liquid metal (CHACC-LM) composite hydrogel with temperature-stress bimodal sensing for smart wearable sensor. LM as liquid fillers toughen the hydrogel matrix (stress: 1.11 MPa) and enhanced the hydrogel extensibility (strain: 233%). The CHACC-LM hydrogel exhibited conductivity (0.6 S/m), excellent antibacterial properties (> 99%), electrical self-healing property and strain sensitivity (GF = 1.6). In addition, the CHACC-LM hydrogel can be used as wearable flexible sensor with the ability of monitoring human activities directly and the distinguished ability of discerning subtle motions (handwriting). It also shown sensitivity in the external environment such as low temperature, thermal response and water solution. Importantly, the composite hydrogel also functioned under stress and different temperature stimuli owing to the existence of LM. Furthermore, the CHACC-LM hydrogel can be used for gesture recognition and to control the manipulator in human-computer interaction. All these properties provide great scope for researchers to achieve practical advances in smart wearable sensor. This article is protected by copyright. All rights reserved.